The education ministry has urged national universities to quickly respond to bullying cases at affiliated schools to prevent repeats of a recent case at a Tokyo high school that left one student severely injured after requests for action were ignored.

On Tuesday, Tokyo Gakugei University Senior High School, one of Japan's top national high schools, admitted to mishandling of bullying incidents that left a student with severe injuries including a bone fracture and concussion.

Tokyo Gakugei University said it took disciplinary action against the head of the high school, located in Tokyo's Setagaya Ward, and four other teachers for failing to report the case for six months.